Burner with an extension of the venturi tube

ABSTRACT

A burner ( 1 ), with natural or forced suction, comprising a burner body ( 2 ), into which a mixture of fuel and air is introduced, said body ( 2 ) being provided with openings ( 4 ) for the flow and subsequent combustion of said mixture and comprising a Venturi tube ( 3 ) into which a jet of said fuel is introduced under pressure and extension means ( 6 ) for said Venturi tube ( 3 ); said extension means ( 6 ) is removably coupled with said Venturi tube ( 3 ).

[0001] The invention relates to a burner with natural or forced suction, equipped with a Venturi tube provided with extension.

[0002] The burners with natural or forced suction known from the prior art, in particular the burners for gaseous fuels, are fed with a mixture of fuel and air that is introduced into the burner through a Venturi tube, mounted inside the burner body. In natural suction burners, the primary air required for the combustion of the fuel is sucked inside the burner through a Venturi tube, due to a dragging effect caused by a jet of fuel under pressure injected into the Venturi tube. In burners with forced suction, obtained through a suction or blowing fan, the primary air required for the combustion is introduced into the burner by the combined effect of the action of the fan and dragging of air produced by the fuel jet injected under pressure into the Venturi tube.

[0003] In burners that require a high amount of primary air, higher than the geometry of the Venturi tube can assures, the above-mentioned dragging effect can be increased by extending the Venturi tube through an extension element having substantially the form of a trumpet, said extension element being mounted at the inlet of the Venturi tube.

[0004] The above-mentioned extension of the Venturi tube is generally mounted in the burner when the burner is manufactured and can not be removed, without damaging the burner itself.

[0005] That limits the flexibility of use of the burner that substantially can be used only at working conditions that require a high amount of primary air.

[0006] It is An object of the present invention to provide a burner with high working flexibility, which can be used in conditions requiring very different primary aeration rates.

[0007] According to the present invention, a burner is provided, with natural or forced suction, comprising a burner body, into which a mixture of fuel and air is introduced, said burner body being provided with openings for the flow and subsequent combustion of said mixture, said body comprising a Venturi tube into which a jet of said fuel is introduced under pressure and extension means for said Venturi tube, characterized in that, said extension means is removably coupled with said Venturi tube.

[0008] That allows said extension means to be mounted only when it is necessary for the working conditions required to the burner and to be dismounted when the working conditions do not require any more the use of said extension means. In such way, a burner is obtained with large flexibility of use, suitable to satisfy a wide range of working requirements.

[0009] The invention will be now described here below, with reference to the enclosed drawings, in which:

[0010]FIG. 1 is an elevation view of a tubular burner according to the invention, provided with an extension element of the Venturi tube;

[0011]FIG. 2 is a top view of FIG. 1;

[0012]FIG. 3 is a partial axial section of the extension element of the Venturi tube;

[0013]FIG. 4 is a side, enlarged view of the extension element of the Venturi tube.

[0014] With reference to the FIG. 1, there are indicated: 1 a burner according to the invention, including a body 2 inside which a Venturi tube 3 is arranged, through the inlet 5 of which a mixture of fuel and air is introduced into the burner 1. The body 2 of the burner 1 is provided, at its upper portion, with openings 3, for example in the form of slots, through which said mixture flows for the subsequent combustion. In the inlet 5 of the Venturi tube 3 an extension element 6 is inserted through which a jet of fuel under pressure is introduced into the Venturi tube 3. An end 7 of the extension element 6, at a distance from the Venturi tube 3, has a flared shape.

[0015] The function of this extension element 6 is to increase the air dragging effect produced by said jet of fuel under pressure, in order to increase the amount of primary air introduced into the body 2 of the burner 1.

[0016] The extension element 6 is removably connected to the Venturi tube 3, so that it can be separated from the Venturi tube 3, when the working conditions of the burner do not require an increase of the amount of the primary air that can be sucked through the Venturi tube 3 alone, and can be reinserted into the Venturi tube 3 when said increase of primary air is required. The connection of the extension element 6 to the Venturi tube 3 can be obtained by means of coupling with slight interference, that assures a stable connection, but easy removable even by hand, between the Venturi tube 3 and the extension element 6.

[0017] Alternatively, the extension element 6 can be connected to the Venturi tube 3 through removable fastening means.

[0018] An example of such a connection type is illustrated in the FIGS. 3 and 4, which show the Venturi tube 3 provided with an internal protrusion 8 insertable into an open slot 9, provided at the end 12 of the extension element 6, that is inserted into the Venturi tube 3. The slot 9 includes a first portion 10, substantially rectilinear and oriented in a direction substantially parallel to the longitudinal axis of the extension element 6, and a second portion 11 preferably arranged at a right angle with respect to said first portion 10. In order to fix the extension element 6 in the Venturi tube 3, it is sufficient to introduce the end 12 into the Venturi tube 3, until said protrusion 8 enters the first portion 10 of the slot 9, and then rotate the extension element 6 so that said protrusion 8 enters the second section 11 of the slot 9, locking in position the extension element 6 in the Venturi tube 3. In order to separate the extension element 6 from the Venturi tube 3 it is sufficient to execute the above-described operations in a reversed order. 

1. Burner (1), with natural or forced suction, comprising a burner body (2), into which a mixture of fuel and air is introduced, said body (2) being provided with openings (4) for the flow and subsequent combustion of said mixture and comprising a Venturi tube (3) into which a jet of said fuel is introduced under pressure and extension means (6) for said Venturi tube (3), characterized in that said extension means (6) is removably coupled with said Venturi tube (3).
 2. Burner (1) according to claim 1, wherein said extension means (6) is coupled to said Venturi tube (3) by means of interference coupling, the measure of said interference being chosen so as to assure stability of the coupling and allow a removal even manual of said extension means (6).
 3. Burner (1) according to claim 1, wherein said extension means (6) is coupled to said Venturi tube (3) through fastening means (8, 9).
 4. Burner (1) according to claim 3, wherein said fastening means (8, 9) includes a protrusion (8) provided on the internal surface of said Venturi tube (3) and an open slot (9) provided at an end of said extension means (6).
 5. Burner (1) according to claim 4, wherein said open slot (9) includes a first portion (10) substantially rectilinear and substantially parallel to a longitudinal axis of said extension means (6).
 6. Burner (1) according to claim 5, wherein said open slot (9) includes a second portion (11) consecutive to said first portion (10) and forming an angle with it.
 7. Burner (1) according to claim 6, wherein said angle has an amplitude of about 90°. 